Fuel injection devices for multicylinder engines



Dec. 9, 1958 P. E. BESSIERE 2,853,437

4FUEIE INJECTION DEVICES FOR MULTICYLINDER ENGINES Filed Jan. 22, 1957FUEL IJECTIN DEVICES FR MULTI- CYLINDER ENGNES Pierre Etienne Bessiere,Paris, France Appiication .lanuary 22, 1957, Serial No. 635,219

Claims priority, application France January 31, 1956 Claims. (Cl.12S-139) The present invention relates to multi-cylinder engine fuelinjection devices in which a single .fuel pump cylinder is connected,thro-ugh a plurality of respective individual conduits, with a pluralityof injectors each of which includes a spindle arranged to open theinjection orice thereof under the effect o-f the pressure of the fuel tobe injected acting thereon against the action of a closing spring.

The object of the present invention is to provide a fuel injectiondevice of this kind which is better adapted to meet the requirements ofpractice than those known at the present time.

For this purpose, in the device according to my invention each of theabove mentioned conduits is controlled by a valve which, during theperiods of time for which no injection is to take place through thecorresponding injector, is held in closing position by an electrowmagnetand which is opened by the pressure of the fuel delivered from the pumpwhen the electro-magnet is brought out of action by control means actingupon the electric feed circuit thereof.

4Preferred embodiments of my invention will be hereinafter describedwith reference to the accompanying drawings, given merely by way ofexample and in which:

Fig. l is an elevational view, partly in section, of an embodiment of afuel injection device according to my invention, for use with a fourcylinder engine.

Figs. 2 and 3 illustrate electro-mechanical means for contro-lling theelectro-magnetic locking means of this device.

The device according to my invention may be used with advantage inconnection with an internal combustion engine including at least twocylinders the cycles of which have a phase difference between them, saidcylinders being fed with fuel from a single fuel feed pump cylinder. Mydevice is for use with diesel engines, spark plug ignition engines,four-stroke engines and two-stroke engines.

On the appended drawings, my invention is supposed to be applied to afour cylinder four-stroke diesel engine fed from a single cylinderinjection pump.

This pump includes a frame 1 in which is journalled the pump drivingshaft 2. A cam 3 fixed on said shaft acts through a push-piece 4 uponthe pump piston S, which reciprocates in the pump cylinder 6. Thiscylinder is provided withrfuel inlet ports 7 through which fuel enterscylinder 6 when piston 5 is in its lowermost position, as shown byFig. 1. Furthermore pump cylinder 6 is provided with a discharge valve 8past which fuel is forced into .delivery conduit 9 by piston 5 aftersaid piston, during its upward movement, has closed inlet po-rts 7.Delivery conduit 9 opens into a chamber 10 from which branch olf four'individual conduits 11a, 11b, 11C, 11d, each of which leads to aninjector 12 mounted on one of the four cylinders of the engine.

Since the engine that is considered is a `four-stroke engine, fuelinjections into the engine cylinders follow ICC one another at intervalscorresponding to a rotation of 180 of the engine shaft. -If the shaft 2of the pump 1 is driven at a speed equal to one half of that of theengine shaft, the successive positions of shaft 2 for which the pump isdelivering fuel are at to one another. Therefore cam 3 includes foursectors so as to achieve four delivery strokes of pump cylinder 5 onevery revolution of shaft 2.

`Of course, on every fuel delivery by pump 1, only one of the fourinjectors 12 connected with this pump is to Work, the three otherinjectors being then nonoperative.

Several distributing devices for this purpose have already beensuggested. But, as a rule, these known devices are complicated andexpensive and their operation is not fully reliable.

These drawbacks are eliminated with the device according to myinvention. In this device, the communication between the conduit 13which, in each injector 12, leads to the injector spindle (not visibleon the drawing) and the corresponding individual feed conduit 11a (or11b, or 11C, or 11d) is controlled `by a valve 14 held in closingposition by electro-magnetic locking means as long as the injector 12`is not to operate. Valve 1@ is mounted in such manner that the fuelpressure in the feed conduit (for instance 11a) tends to open it so thatfuel can pass freely into `conduit 13 as soon as the electromagneticlocking means .are brought out of action.

Valve 14 and its electro-magnetic locking means may Vbe mounted in alateral projection 15, made of a magnetic material, of the body ofinjector 12.

Advantageously, as shown by the drawing, the electro-magnetic lockingmeans include a coil 16 housed in a circular groove'provided in part 15so that the combination of said coil 16 with the magnetic walls whichsurround it constitutes a circular electro-magnet running around acylindrical recess in which is slidably mounted a plunger 14. Adisc-shaped armature 17, made of a magnetic material is rigid with saidplunger 14. Advantageously, the disc constituted by armature 17 isprovided with holes 17a extending throughout it so as to reduce itsaerodynamic resistance to movement. A return spring 18 urges saidarmature 17 toward coil 16 during the suction stroke of the fuel pumppiston.

Plunger 14, slidable in cylindrical recess 19, which is in communicationwith conduit 11a, controls the opening of a passage branching olf fromsaid recess 19 and forming the end of conduit 13 which leads to theinjector spindle. This arrangement makes it possible to avoid any airgap in the electromagnetic locking means without risk of thefuel-tightness of the valve being impaired by normal Wear and tear.

As long as a current of sufficient intensity is flowing through coil 16,the fuel pressure transmitted through conduit 11a which is acting uponthe end of plunger 14 is insufficient to overcome the locking actionexerted by electro-magnet 16 upon armature 17, Plunger 14 cuts off thecommunication between recess 19 and conduit 13. On the contrary, Whenthe current flowing; through coil 16 is reduced or cut off, the fuelunder pressure in cylinder 19 lifts plunger 14 and flows to the injectorspindle which is opened by the fuel pressure, so that fuel is injectedinto the engine cylinder by the injector.

An electric control member, for instance in the form of a rotary switch20 (Fig. 2) controls the operation of the electromagnetic locking means,each of said means in succession being temporarily brought out of actionfor the period during which injection is to take place into thecorresponding engine cylinder.

This control member may cut off, vduring a suitable time period, theenergizing current which `is normally flowing through the coilsof thelocking :means (these coils being designated on Fig. 2 by the referencenumerals 16a, 1Gb, 16e, 16d);

In the embodiment illustrated by Fig. 2, arotating switch controls theoperation of valves 14. This switch comprises a rotating cylinder 20 ofa conductor material carrying four rings on which are slidably appliedbrushes 41a, 41h, 41e, 41d inserted in the respective individualcircuits of coils 16a, 16h, 16C and 16d. These circuits are connected inshunt fashion with one of the terminals of a current source 22 the otherterminal of which is connected through a brush 23 with the body 20 ofthe switch. Each of the above mentioned rings includes two portions,respectively 21a and 21a, 2lb and 21'11, 21C and 21c, 21d and 21d.Portions 21a, 21'b, 21c and Zlfd are off-set with respect to one anotheron the rotary switch body 20 so as to obtain the desired time oifsettingbetween their actions on therrespective coils 16a, 16b, 16e and 16d.Switch body 2t) is for instance fixed on shaft 2 by key 36.

If, as above supposed, coils 16a, 16h, 16's and 16d f are arranged sothat, when a sufficient current flows therethrough, they keep therespective valves locked in closed position, sections 21a, 2lb, 21C and21d are made of a conductor material so as to close the circuits of saidcoils. As for sections 21a, 21'b, 21'c and 21d, they are insulating orlittle conductive (then forming resistances) so as to cut ott or tolower the current flowing through said coils. It may also be supposedthat armatures 17 are normally magnetized to be yieldingly applied onpiece 15 and that windings 16a, 16h, 16e and 16d are demagnetizingwindings. In this case, portions 21a, 2lb, 21e and 21d of the rings aremade of insulating or little Conductive material and portions 21'a, 21b,21c and 21d of conductive material.

The operation of the above described fuel injection device is as followsif it is supposed that coils 16a, 16h, 16e, 16d are magnetizingwindings, that portions 21a, 2lb, 21C, 21d are conductors and thatportions 21'a, 21b, 21c, 21d are insulators:

During one complete revolution of shaft 2, which corresponds to tworevolutions of the engine shaft, four successive delivery strokes ofinjection pump 1-8 take place. During each of these delivery strokes thevalve 14 of one of the four injectors 12 successively is released sothat, every time, injection takes place in a different engine cylinder.As soon as the fuel pressure on the end of plunger 14 ceases to exist(which is due either to the end of the delivery stroke or to the openingof an outlet port in the delivery circuit) return spring 18 closes thecorresponding valve 14. At the same time the armature 17 of theelectromagnetic locking means is returned on to the correspondingelectro-magnet 16, where it remains applied due to the fact that theenergizing current is once more flowing through the correspondin coil. t

Adjustment of the amount of fuel fed to every engine cylinder on everyoperation of the injector thereof may be obtained through any suitablemeans, for instance by the use of a valve controlling a leak or bleedorifice provided in the fuel feed pipe leading to the injector.

According to a particularly advantageous embodiment illustrated by thedrawings, such a valve, shown at 24 is provided in the delivery circuitof the pump upstream of the point where conduit 8 branches off to formindividual conduits 11a, 11b, 11C, 11d leading to the respectiveinjectors. In the embodiment illustrated by the drawing, this valve istherefore mounted in the wall of chamber 10.

Valve 24 is kept applied upon its seat by an electromagnet including awinding 25 housed in a recess of a support of magnetic material 26, soas to constitute two concentric annular terminals 27 and 28 whichcooperate with an armature 29 urged in the downward direction both bythe pulling action of electro-magnet' 25-26 and by the resilient actionof a return spring 30.

4 As long as an energizing current of a given intensity is flowingthrough winding 25, valve 24 closes the leak orifice 31 provided in thewall of chamber 10 (Fig. l). As soort as the current flowing throughwinding 25 is reduced or cut off, valve 24 opens and causes fuel to owout through said orifice 31 and a second orifice 32 located downstreamof valve 24, which immediatelyI stops injection due to the sudden dropof pressure through conduits 9, 10, 11, so that valve 14 can close.

The fuel flowing out through orifice 32 is returned to the fuel tank orto the suction conduit of pump 1-8 through a passage which is not shown.

The energizing current of winding 25 may be controlled through anysuitable means. However, advantageously, I make use of a rotating switch(Fig. 3) constituted by a stationary brush 33 in contact with a cylinder rotated by the engine. This cylinder has its surface 34 constitutedby a conductive material capable of cooperating with brush 33 so as toclose the circuit of winding 25. In this conducting surface 34 areprovided as many insulating strips 3S as there are separate fuelinjections for one revolution of the rotating cylinder. In the caseshown by the drawing, where said cylinder is driven by shaft 2, whichalso drives cam 3, the number of these strips is four. Each strip 35 hasparallel edges oblique with respect to the generatrices of the cylinder.These insulating strips are disposed, with respect to the insulatingareas 21a, 2lb, 21C and 21d of switch 2t) (Fig. 2) in such manner thatcurrent is cut off in winding 25 generally after it is cut off in eachof the coils 16a, 1Gb, 16C and 16d of the injectors and after thebeginning of the delivery stroke of the pump. T he exact time at whichthe energizing current is cut off in winding 25,v

and consequently the amount of fuel injected by each of the injectorsmay be modified by relative longitudinal displacement of the cylinderand of brush 3 with respect to each other, for instance by slidingdisplacement of the cylinder on shaft 2 with respect to brush 33 (asshown in dotted lines on Fig. 3). The cylinder is driven by shaft 2 bymeans of feather key 37. It can be made to slide along shaft 2 by meansof forked lever 38.

In a general manner, while I have, in the above description, disclosedwhat I deem to be practical and ecient embodiments of my invention, itshould be well understood that I do not wish to be limited thereto asthere might be changes made in the arrangement, disposition and form ofthe parts without departing from the principle of the preent inventionas comprehended within the scope of the accompanying claims.

What I claim is:

l. For use in connection with an internal combustion engine having atleast two cylinders the working cycles of which have a phase dierencebetween them, a fuel injection device which comprises, in combination, arecip-y rocating action fuel feed pump including a single4 cylinder, aninjector mounted on each of said engine cylinders respectively,individual conduits extending each between the output of said pump andone of said injectors respectively, a valve in each of said conduitsupstream of the injector located at the end of said conduit, said valvebeing arranged to cut oif, when it is closed, the ow of fuel throughsaid last mentioned conduit, said valve being arranged to be urgedtoward opening position by the pressure of fuel in said last mentionedconduit upstream of said valve, an electro-magnet mounted to cooperatewith each of said valves to hold it normally in closed position,electric means for normally holding said electromagnets operative forsaid purpose and means operatively connected with said pump for makingeach of said electro-magnets in its turn inoperative for a period oftime during one delivery stroke of said pump.

2. A device according to claim l in which each of said valves includes abody provided with a cylindrical recess communicating at one end withthat of said individual conduits which is controlled by said valve and aplunger slidable in said recess and rigid with the armature of thecorresponding electro-magnet, the fuel passage of that of said injectorswhich is fed through said last mentioned conduit opening into thecylindrical Wall of said recess, said passage being closed by saidplunger when said electro-magnet is energized.

3. A device according to claim 2 in which said valve body is integralwith the body of the corresponding injector.

4. A device according to claim l further including a valve for theoutlet of fuel from the output of said pump to stop fuel injection, saidlast mentioned valve being located at the output of said pump, upstreamof the point Where said individual conduits branch off therefrom, and

electro-magnetic means for controlling the opening of said outlet valve.

5. A device according to claim 4 including a chamber in directcommunication with the output of said pump, said individual conduitsbranching oil` from said chamber, said chamber being provided with anoutlet orifice and said outlet valve being mounted in the wall of saidchamber to control said orifice.

References Cited in the file of this patent UNITED STATES PATENTS2,356,134 voit Aug. 22, 1944

